Clock recovery is used in a variety of communications network applications to enable nodes using different clocks to operate in an effectively synchronized manner. When a client provides a traffic signal (e.g., Ethernet or synchronous optical networking (SONET) signal), a higher-rate signal may transport that client traffic signal from an ingress side of a network using standards such as Generic Frame Protocol (GFP) or Optical Transport Unit (OTU) signals. Certain standards govern the requirements for such higher-rate signals and must be adhered to for reliable data transmission. For example, with regard to SONET, Generic Requirement 253 (GR-253) provides jitter and wander performance requirements. After the higher rate signal traverses the network, the client traffic signal is stripped out of the higher-rate signal at an egress side of the network. The signal may be bursty, such as in the case of Ethernet, and may be susceptible to wander and jitter. However, the client will want to acquire the original frequency at which the client traffic signal arrived at the ingress side.
One existing method uses a differential clock recovery method in which phase information, relative to a clock that is common to both the ingress and egress data path, is included in a traffic signal as overhead and sent from the client ingress side to the client egress side in order to assist the egress side in recovering the client's phase. This method requires a common clock to be available to both the ingress and egress sides of the connection as well as the use of overhead bytes to send the phase information between two network nodes. However, not all systems or network architectures include a reference clock or have a reference clock available, and organizations may prefer not to have to comply with such a requirement or to equip network nodes with complex circuits to support reference clocks and phase corrections thereof.